Enlarging roller cutter



l 1965 KARL-GUNTER BECHEM 3,204,710

ENLARGING ROLLER CUTTER Filed March 12, 1962 wwmmwm r fi /NENTU P Karl-Gunl'er Beohem Q! "I E m l A-Hornqs United States Patent "3,204,710 ENLARGENG ROLLER CUTTER Karl-Gunter Bechem, Hagen-Berchurn, Westphalia, Germany, assignor to J. C. Soding 8; Halhach, Hagen, Westphalia, Germany, a corporation of Germany Filed Mar. 12,, 1962, Ser. No. 178,950 Claims priority, application Germany, Mar. 13, 1961, B 61,648 7 Claims. (Cl. 175-644) The invention relates to a roller cutter with one annular tooth disposed on a roller base member.

It is an object of the invention to produce an enlarging roller cutter which enables the bottom of the drilled hole to be cut back while drilling is in progress, and enables the drilled annular material which has been released to be thrown towards the drilled starting hole.

According to the invention there is provided an enlarging roller cutter with one annular tooth disposed on a roller base member, charcterised in that the annular tooth is disposed at the forward free end of a roller base member, and a free surface is left behind the said annular tooth, said cutter being designed to widening or enlarg' ing a previously drilled or pilot hole.

If the bottom of the drilled hole is of corresponding width, or the scarf is of a corresponding nature, it is pos sible that the annular tooth will inded cut in, but will not have enough force to throw the drilled annular material towards the starting hole.

Accordingly, in one embodiment of the invention, the free surface of the roller base member behind the said annular tooth is made in at least substantially conical form with projecting extensions, so that this part of the base member rolls down onto the drilled annular material, which may if desired be left stationary, thus crushing it and moving it off towards the starting hole.

In another embodiment of the invention, the free surface of the roller base member which is behind the annul-ar tooth is the surface of a prism. However, this surface may also be made in the form of a smooth cone comprising extensions, preferably teeth, which may be interchangeable.

In order that the invention may be well understood there will now be described some embodiments thereof, given by way of example only, reference being had to the accompanying drawing, in which:

FIGURE 1 shows a part-sectioned lateral elevation of a roller cutter according to the invention; and

FIGURES 2 and 3 show sections along the line IIII of two different forms of embodiment of a roller cutter according to the invention.

It may be seen from FIGURE 1 that an annular tooth 5 is screwed on to the forward end of a base member 4, which is fitted on to a stud 1 via ball and roller bearings 2, 3, if desired with the interposition of a bushing. The annular tooth 5 works on the bottom 6 of a drilled hole, and cuts it back at the point 7. Normally, that part of the bottom of the drilled hole which extends inwards from the point 7 breaks off towards the starting hole after a certain depth of penetration has been attained. However, if the bottom 6 of the drilled hole is of corresponding width, or if the annular shoulder is of an unfavourable nature, it is possible that the annular tooth 5 will work completely into the bottom of the drilled hole at '7, so that the external surface of the base member 4 comes to bear against the bottom of the drilled hole. In this case, the drill then rotates idly. According to the invention, assistance is provided here by the fact that a stir face 8 of the base member which follows behind the annular tooth 5 is of at least substantially conical form, so that this part works on the bottom of the drilled hole and crushes it, thus facilitating throw-off by the annular tooth.

FIGURE 2 shows this surface designed as a hexagon, while FIGURE 3 shows extensions 9 fitted to the said surface. The said extensions may be interchangeable, and it is furthermore expedient for them to be made of a more wear-resistant material than the base member 4.

The invention is naturally not limited to the forms of embodiment hereinbefore described in detail and illustrated in the drawings, but on the contrary numerous modifications are possible without departing from the basic idea of the invention.

I claim:

1. Enlarging roller cutter for widening a pilot hole comprising a stud, a roller base mounted thereon, a single annular tooth attached at the forward end of said base, the diameter of said tooth being substantially greater than that of said base, the surface of said base having a plurality of longitudinal extensions providing rib-like edges adapted to crush material cut by said tooth, a free area is provided to the rear of said tooth to accommodate the material adopted to be cut away by said tooth and allow said material to fall into said pilot hole.

2. A cutter according to claim 1 characterized in that said base tapers rearwardly from said tooth.

3. Enlarging roller cutter for widening a .pilot hole comprising a stud, a roller base mounted thereon, a single annular tooth attached at the forward end of the base, the diameter of said tooth being substantially greater than that of said base, the surface of said base having a plurality of irregularities adapted to crush cut material, the area between said surface and the rearward projection of the tooth diameter constituting a free area to accommodate the material adapted to be cut away by said tooth and to allow said material to fall into said pilot hole, and characterized in that said base has a polygonal surface.

4. Enlarging roller cutter for widening a pilot hole comprising a stud, a roller base mounted thereon, a single annular tooth attached at the forward end of the base, the diameter of said tooth being substantially greater than that of said base, the surface of said base having a plurality of irregularities adapted to crush cut material, the area between said surface and the rearward projection of the tooth diameter constituting a free area to accommodate the material adapted to be cut away by said tooth and to allow said material to fall into said. pilot hole, and characterized in that said base has a non-circular surface.

5. Enlarging roller cutter for widening a pilot hole comprising a stud, a roller base mounted thereon, a single annular tooth attached at the forward end of the base, the diameter of said tooth being substantially greater than that of said base, the surface of said base having a plurality of irregularities adapted to crush cut material, the area between said surface and the rearward projection of the tooth diameter constituting a free area to accommodate the material adapted to be cut away by said tooth and to allow said material to fall into said pilot hole, and characterized in that said base has projections thereon.

6. Enlarging roller cutter for widening a pilot hole comprising a stud, a roller base mounted thereon, a single annular tooth attached at the forward end of the base, the diameter of said tooth being substantially greater than that of said base, the surface of said base: having a plurality of irregularities adapted to crush cut material, the area between said surface and the rearward projection of the tooth diameter constituting a free area to accommodate the material adapted to be cut away by said tooth and to allow said material to fall into said pilot hole, and

characterized in that said base has projections thereon, said projections being more wear-resistant than said base.

7. Enlarging roller cutter for widening a pilot hole comprising a stud, a roller base mounted thereon, a single annular tooth attached at the forward end of the base, the diameter of said tooth being substantially greater than that of said base, the surface of said base having a plurality of irregularities adapted to crush cut material, the area between said surface and the rearward projection of the tooth diameter constituting a free area to accommodate the material adapted to be cut away by said tooth and to allow said material to fall into said pilot hole, and characterized in that the inner face of said tooth is threaded and is fitted onto corresponding threads on said base.

References Cited by the Examiner UNITED STATES PATENTS 12/03 Muller 175-334 X 8/15 Decker 175391 X 2/30 Seifert l75391 X 2/30 Seifert 175-344 X 5/41 Hatcher 175350 X 1/62 Woodruff 175-344 6/62 Risse 262--15 FOREIGN PATENTS 12/60 France.

7/07 Germany. 6/ 64 Great Britain.

CHARLES E. OCONNELL, Primary Examiner. 

1. ENLARGING ROLLER CUTTER FOR WIDENING A PILOT HOLE COMPRISING A STUD, A ROLLER BASE MOUNTED THEREON, A SINGLE ANNULAR TOOTH ATTACHED AT THE FORWARD END OF SAID BASE, THE DIAMETER OF SAID TOOTH BEING SUBSTANTIALLY GREATER THAN THAT OF SAID BASE, THE SURFACE OF SAID BASE HAVING A PLURALITY OF LONGITUDINAL EXTENSIONS PROVIDING RIB-LIKE EDGES ADAPTED TO CRUSH MATERIAL CUT BY SAID TOOTH, A FREE AREA IS PROVIDED TO THE REAR OF SAID TOOTH TO ACCOMMODATE THE MATERAIL ADOPTED TO BE CUT AWAY BY SAID TOOTH AND ALLOW SAID MATERIAL TO FALL INTO SAID PILOT HOLE. 